Honduras slid toward greater instability after soldiers blocked an airport runway to prevent the return of ousted President Manuel Zelaya, and largely peaceful protests yielded their first death. Police and soldiers blanketed the streets of the capital overnight Monday with a sunset-to-sunrise curfew. The extended clampdown added to the tension after a tumultuous Sunday during which soldiers clashed with thousands of Zelaya backers who massed at the airport in hopes of welcoming home their deposed leader. Zelaya's plane, on loan from Venezuelan President Hugo Chavez, arrived to find the runway blocked by military vehicles and soldiers under the command of the government that has ruled the Central American country since Zelaya's ouster last weekend. The Venezuelan pilots circled around the airport but ended up deciding not to risk a crash. Zelaya instead headed for El Salvador, vowing to try again Monday or Tuesday to return to power in a country where all branches of government have lined up against him. "I call on the Armed Forces of Honduras to lower their rifles," he said late Sunday at a news conference, flanked by the presidents of El Salvador, Argentina, Paraguay and Ecuador, and the secretary-general of the Organization of American States, Jose Miguel Insulza, who flew there from Washington. "I am risking myself personally to resolve the problems without violence," said Zelaya, who planned to fly later to Nicaragua. He urged the United Nations, the OAS, the United States and European countries to "do something with this repressive regime." Insulza said he "is open to continuing all appropriate diplomatic overtures to obtain our objective." But interim Honduran President Roberto Micheletti said he won't negotiate until "things return to normal." "We will be here until the country calms down," Micheletti said. "We are the authentic representatives of the people." Clashes broke out Sunday afternoon between police and soldiers and the huge crowd of Zelaya supporters surrounding Tegucigalpa's international airport. At least one man was killed - shot in the head from inside the airport as people tried to break through a security fence, according to an Associated Press photographer at the scene. At least 30 people were treated for injuries, the Red Cross said, after security forces fired warning shots and tear gas. When Zelaya's plane was turned away, his supporters began chanting "We want blue helmets!" - a reference to UN peacekeepers. Zelaya won wide international support after his ouster, but several presidents who originally were to accompany him decided it was too dangerous to fly on Zelaya's plane, which carried only his close advisers and staff, two journalists from the Venezuela-based network Telesur and U.N. General Assembly President Miguel D'Escoto Brockmann, a leftist Nicaraguan priest and former foreign minister. Honduras' new government has vowed to arrest Zelaya for 18 alleged criminal acts including treason and failing to implement more than 80 laws approved by Congress since taking office in 2006. Zelaya also refused to comply with a Supreme Court ruling against his planned referendum on whether to hold an assembly to consider changing the constitution. Critics feared Zelaya might try to extend his rule and cement presidential power in ways similar to what his ally Chavez has done in Venezuela - though Zelaya denied that. But instead of prosecuting him or trying to defeat him at the ballot box, masked soldiers flew the president out of the country at gunpoint, and Congress installed Micheletti in his place.